[PATCH weston v4 14/20] clients/resizor: Use pointer locking for resizing window

[Peter Hutterer]

On Tue, Nov 17, 2015 at 06:11:00PM +0800, Jonas Ådahl wrote:
> Resizes the window using pointer locking when holding the left pointer
> button down. The pointer lock cursor position hint is used to warp the
> pointer to the same position relative to the bottom right corner.
> 
> Signed-off-by: Jonas Ådahl <jadahl at gmail.com>
> ---

don't know the resizor code well enough, but nothing jumping out at me as
obviously wrong here :)

Reviewed-by: Peter Hutterer <peter.hutterer at who-t.net>

Cheers,
   Peter

>  clients/resizor.c | 159 ++++++++++++++++++++++++++++++++++++++++++++++++++++--
>  1 file changed, 154 insertions(+), 5 deletions(-)
> 
> diff --git a/clients/resizor.c b/clients/resizor.c
> index d205eb6..95e16ea 100644
> --- a/clients/resizor.c
> +++ b/clients/resizor.c
> @@ -23,6 +23,7 @@
>  
>  #include "config.h"
>  
> +#include <stdbool.h>
>  #include <stdint.h>
>  #include <stdio.h>
>  #include <stdlib.h>
> @@ -50,6 +51,10 @@ struct resizor {
>  	struct spring width;
>  	struct spring height;
>  	struct wl_callback *frame_callback;
> +	bool pointer_locked;
> +	struct input *locked_input;
> +	float pointer_x;
> +	float pointer_y;
>  };
>  
>  static void
> @@ -220,20 +225,158 @@ show_menu(struct resizor *resizor, struct input *input, uint32_t time)
>  }
>  
>  static void
> +locked_pointer_handle_motion(struct window *window,
> +			     struct input *input,
> +			     uint32_t time,
> +			     float dx,
> +			     float dy,
> +			     void *data)
> +{
> +	struct resizor *resizor = data;
> +
> +	resizor->width.current += dx;
> +	resizor->width.previous = resizor->width.current;
> +	resizor->width.target = resizor->width.current;
> +
> +	resizor->height.current += dy;
> +	resizor->height.previous = resizor->height.current;
> +	resizor->height.target = resizor->height.current;
> +
> +	widget_schedule_resize(resizor->widget,
> +			       resizor->width.current,
> +			       resizor->height.current);
> +}
> +
> +static void
> +handle_pointer_locked(struct window *window, struct input *input, void *data)
> +{
> +	struct resizor *resizor = data;
> +
> +	resizor->pointer_locked = true;
> +	input_set_pointer_image(input, CURSOR_BLANK);
> +}
> +
> +static void
> +handle_pointer_unlocked(struct window *window, struct input *input, void *data)
> +{
> +	struct resizor *resizor = data;
> +
> +	resizor->pointer_locked = false;
> +	input_set_pointer_image(input, CURSOR_LEFT_PTR);
> +}
> +
> +static const struct wl_callback_listener locked_pointer_frame_listener;
> +
> +static void
> +locked_pointer_frame_callback(void *data,
> +			      struct wl_callback *callback,
> +			      uint32_t time)
> +{
> +	struct resizor *resizor = data;
> +	struct wl_surface *surface;
> +	struct rectangle allocation;
> +	float x, y;
> +
> +	if (resizor->pointer_locked) {
> +		widget_get_allocation(resizor->widget, &allocation);
> +
> +		x = resizor->pointer_x + (allocation.width - allocation.x);
> +		y = resizor->pointer_y + (allocation.height - allocation.y);
> +
> +		widget_set_locked_pointer_cursor_hint(resizor->widget, x, y);
> +	}
> +
> +	wl_callback_destroy(callback);
> +
> +	surface = window_get_wl_surface(resizor->window);
> +	callback = wl_surface_frame(surface);
> +	wl_callback_add_listener(callback,
> +				 &locked_pointer_frame_listener,
> +				 resizor);
> +}
> +
> +static const struct wl_callback_listener locked_pointer_frame_listener = {
> +	locked_pointer_frame_callback
> +};
> +
> +static void
>  button_handler(struct widget *widget,
>  	       struct input *input, uint32_t time,
>  	       uint32_t button, enum wl_pointer_button_state state, void *data)
>  {
>  	struct resizor *resizor = data;
> +	struct rectangle allocation;
> +	struct wl_surface *surface;
> +	struct wl_callback *callback;
>  
> -	switch (button) {
> -	case BTN_RIGHT:
> -		if (state == WL_POINTER_BUTTON_STATE_PRESSED)
> -			show_menu(resizor, input, time);
> -		break;
> +	if (button == BTN_RIGHT && state == WL_POINTER_BUTTON_STATE_PRESSED) {
> +		show_menu(resizor, input, time);
> +	} else if (button == BTN_LEFT &&
> +		   state == WL_POINTER_BUTTON_STATE_PRESSED) {
> +		window_get_allocation(resizor->window, &allocation);
> +
> +		resizor->width.current = allocation.width;
> +		resizor->width.previous = allocation.width;
> +		resizor->width.target = allocation.width;
> +
> +		resizor->height.current = allocation.height;
> +		resizor->height.previous = allocation.height;
> +		resizor->height.target = allocation.height;
> +
> +		window_lock_pointer(resizor->window, input);
> +		window_set_pointer_locked_handler(resizor->window,
> +						  handle_pointer_locked);
> +		window_set_pointer_unlocked_handler(resizor->window,
> +						    handle_pointer_unlocked);
> +		resizor->locked_input = input;
> +
> +		surface = window_get_wl_surface(resizor->window);
> +		callback = wl_surface_frame(surface);
> +		wl_callback_add_listener(callback,
> +					 &locked_pointer_frame_listener,
> +					 resizor);
> +	} else if (button == BTN_LEFT &&
> +		   state == WL_POINTER_BUTTON_STATE_RELEASED) {
> +		input_set_pointer_image(input, CURSOR_LEFT_PTR);
> +		window_unlock_pointer(resizor->window);
>  	}
>  }
>  
> +static void
> +set_cursor_inv_offset(struct resizor *resizor, float x, float y)
> +{
> +	struct rectangle allocation;
> +
> +	widget_get_allocation(resizor->widget, &allocation);
> +
> +	resizor->pointer_x = x - (allocation.width - allocation.x);
> +	resizor->pointer_y = y - (allocation.height - allocation.y);
> +}
> +
> +static int
> +enter_handler(struct widget *widget,
> +	      struct input *input,
> +	      float x, float y, void *data)
> +{
> +	struct resizor *resizor = data;
> +
> +	set_cursor_inv_offset(resizor, x , y);
> +
> +	return CURSOR_LEFT_PTR;
> +}
> +
> +static int
> +motion_handler(struct widget *widget,
> +	       struct input *input, uint32_t time,
> +	       float x, float y, void *data)
> +{
> +	struct resizor *resizor = data;
> +
> +	set_cursor_inv_offset(resizor, x , y);
> +
> +	return CURSOR_LEFT_PTR;
> +}
> +
>  static struct resizor *
>  resizor_create(struct display *display)
>  {
> @@ -251,6 +394,12 @@ resizor_create(struct display *display)
>  	window_set_keyboard_focus_handler(resizor->window,
>  					  keyboard_focus_handler);
>  
> +	widget_set_enter_handler(resizor->widget, enter_handler);
> +	widget_set_motion_handler(resizor->widget, motion_handler);
> +
> +	window_set_locked_pointer_motion_handler(
> +			resizor->window, locked_pointer_handle_motion);
> +
>  	widget_set_button_handler(resizor->widget, button_handler);
>  
>  	resizor->height.previous = 400;
> -- 
> 2.4.3
> 
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